Sometimes people have trouble getting started because they're overwhelmed by everything they have to do. Learn to say no. Learn to renegotiate. Stop dicking around and tell someone "I'm sorry, I thought I'd be able to do this, but I haven't got time at the moment". Then get on with something more important.
Link to this | This doesn't fucking apply to me
Bonus points: learn a tactic to help with avoiding this in future – the qualified yes.